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RC1 82.S2  D85        A  study  of  1 153  case 


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A   STUDY    OF    1153    CASES    OF 
SCARLET    FEVER 

WITH    ESPECIAL   REFERENCE  TO 
THEIR    SEQUELAE 


Read  before  The  Southeastern  Sanitary  Association,  Bruns- 
wick, Ga.,  March  24,  1916 


BY 

LOUIS  I.  DUBLIN,  Ph.D.,  Statistician 
Metropolitan  Life  Insurance  Company,  New  Yorli 

1916 


V 


9  0    > 


'S^^ 


A  Study  of  1,153  Cases  of  Scarlet 
Fever 

WITH    ESPECIAL   REFERENCE  TO   THEIR   SEQUELAE* 


LOUIS     L    DUBLIN,     Ph.D. 

Statistician,    Metropolitan    Life    Insurance    Company 
NEW     YORK 


It  is  the  primary  purpose  of  this  paper  to  report  on 
an  investigation  into  the  sequelae  of  scarlet  fever.  It 
has  been  possible,  in  addition,  to  examine  some  general 
characteristics  of  the  cases  under  review,  and  these, 
too,  will  be  considered  in  the  report.  The  plan  which 
has  been  followed  was  developed  in  a  study  of  the 
sequelae  of  typhoid  fever,^  namely,  to  trace  the  condi- 
tion of  the  survivors  of  the  disease  as  far  as  is  pos- 
sible through  an  interval  of  four  or  five  years  subse- 
c[uent  to  recovery,  and  to  note  especially  the  occur- 
rence of  any  undue  number  of  deaths  during  this 
period  from  causes  which  may  be  considered  sequelae 
of.  the  primary  disease.  In  the  case  of  typhoid  fever, 
I  was  able  to  show  that,  in  a  series  of  1,428  cases  in 
which  the  patients  had  survived  the  attack  of  that 
disease,  the  mortality  during  the  three  following  years 
was  twice  as  great  as  was  to  be  expected  from  the 
age,  sex,  and  color  of  the  group.  This  high  rate  of 
mortality  resulted  from  an  increase  in  the  number  of 
deaths  from  tuberculosis  and  organic  heart  disease. 
In  view  of  the  well  known  effect  exerted  by  scarlet 
fever  on  the  heart  and  kidney  tissues,  it  seemed  likely 
that  an  analogous  condition  of  high  subsequent  mor- 
tality might  be  found  to  prevail.  In  any  case,  it  was 
desired  to  measure  exactly  the  conditions  which 
actually  arise. 

The  records  of  the  Visiting  Nurse  Service  of  the 
Metropolitan  Life  Insurance  Company  again  gave  us 

*  The  writer  is  indebted  to  Dr.  Lee  K.  Frankel  for  his  courtesy  in 
putting  the  records  of  the  Visiting  Nurse  Service  of  the  Metropolitan 
Life   Insvirance   Company   at   his   disposal   for   this   study. 

1.  Dublin,  L.  I.:  Typhoid  Fever  and  Its  Sequelae,  Am.  Jour.  Pub. 
Health,    1915,   v.    No.    1. 

1 


the  original  material  for  the  investigation.  There 
were  1,153  cases  of  scarlet  fever  in  the  two  years  1911 
and  1912  among  white  persons.  The  patients  were 
all  treated  by  physicians.  The  accuracy  of  the  diag- 
nosis was  in  little  or  no  doubt,  and  the  records  in  other 
respects  were  fairly  complete  and  trustworthy.  The 
patients  were  all  policyholders  of  the  company,  and 
their  whereabouts  and  physical  condition  could  readily 
l)e  traced  during  the  subsequent  years.  For  those 
patients  who  died,  full  and  comprehensive  medical 
records  were  at  hand  for  examination. 

Table  1  shows  the  distribution  of  the  1,153  primary 
cases  by  sex  and  by  age  period. 


TABLE    1.— DISTRIBUTION    OP    1,153    CASES    OP    SCARLET    FEVER 
BY     SEX    AND     AGE 


Age 

Males  and  Females 

Males 

Females 

Number ;  Per  Cent. 

Number 

Per  Cent. 

Number 

Per  Cent. 

All  Ages 

1,153             100.0 

941       [        81.6 

503              43.6 

103                8.9 
132              11.4 
148              12.8 
120              10.4 

438              38.0 

123              10.7 
114       i          9.9 
76       !          6.6 
65       1          5.6 
60                5.2 

132              11.4 
43                3.7 
24      ,          2.1 
13                1.1 

501 
433 
254 

63 

57 
73 
61 

179 

54 
47 
31 
22 

25 

53 

11 

4 

100.0 

86.4 

50.7 

12.6 
11.4 
14.6 
12.2 

35.7 

10.8 
9.4 
6.2 
4.4 
5.0 

10.6 
2.2 
0.8 

652 
508 
249 
40 

lOO.O 

2  to  10 

77.9 

2  to    5 

2 

38.2 
6.1 

3 

75              11.5 

4 

5 

6  to  10 

75       1        11.5 
59                9.0 

259              39.7 

6 

7 

8 

69              10.6 
67              10.3 
45                6.9 

9 

10 

11  to  15 

43 
35 

79 

6.6 
5.4 

12.1 

16  to  20 

32 
20 
13 

4.9 

21  to  30 

3  1 

31  to  40 

20 

Nearly  82  per  cent,  of  all  the  cases  were  among 
children  between  2  and  10 ;  the  company  has  no  policy- 
holders in  the  first  year  of  life.  The  greatest  disposi- 
tion to  the  disease  is  found  among  children  from  3  to 
7  years  of  age  ;  637  cases,  or. 55.2  per  cent,  of  the  total, 
were  found  within  these  five  years  of  life.  The  period 
11  to  15  presents  an  appreciable  number  of  cases;  but 
after  this  period  the  cases  are  few  and  far  between, 
all  of  them  amounting  to  only  6.9  per  cent,  of  the 
total.  We  are,  therefore,  concerned  primarily  with 
children.  In  this  respect  our  series  agrees  substan- 
tially with  other  scarlet  fever  series.  McCollom,  for 
example^  reports  that  75  per  cent,  of  his  patients 
treated  at  the  Boston  City  Hospital  were  between  the 


ages  of  2  and  10,  and  50  per  cent,  between  the  ages  of 
3  and  7.  The  figures  for  Willard  Parker  Hospital 
cases  are  very  similar.  There  is  apparently  no  impor- 
tant distinction  in  this  respect  between  the  two  sexes. 

Not  only  are  the  children  at  the  youngest  ages  more 
susceptible  to  scarlet  fever,  but  it  appears  that  these 
children  also  take  the  disease  in  the  severest  form. 
This  is  evidenced  by  Table  2,  which  presents  lethal 
rates  for  the  number  of  deaths  per  hundred  cases 
treated,  classified  by  age. 

There  were  in  all  ninety  deaths  in  the  total  of  1,153 
cases ;  this  represents  a  lethal  rate  of  7&  per  cent.  At 
age  2,  next  birthday,  15.5  died  out  of  every  hundred 


TABLE  2.-LETHAL  RATES  PER  HUNDRED  CASES  TREATED 
EOR  SCARLET  FEVER,  CLASSIFIED  BY  AGE 


Age 

Number 
Treated 

'      Number 
Died 
Under 
Treatment 

Lethal 

Rate 

per  100  Cases 

Treated 

1,153 

941 

503 

103 

132       . 
148 
120 

438 

123 
114 

70 

55 

60 

132 
43 
24 
13 

90 

83 

51 

16 
16 
11 

8 

32 

14 

7 

6 

2 

4 
1 
1 
1 

7.81 

2  to  10.... 
2  to    5.... 

9 

8.82 
10.14 
15.53 

12.12 

4 

7.43 

5 

6.67 

6  to  10.... 
(i 

7.31 

13.38 
6.14 

8 

9 

10 

11  to  15.... 

3.95 
9.23 
3.33 

3.03 

16  to  20.... 
21  to  30. . . . 
31  to  40.... 

2.33 
4.17 
7.69 

treated.  For  the  age  period  2  to  5  the  lethal  rate  is 
10.1,  and  for  the  entire  period  2  to  10  the  lethal  rate 
is  8.8.  Thereafter  the  lethal  rate  decreases  very 
appreciably.  The  very  high  figure  for  the  age  period 
31  to  40  is  of  no  significance,  since  the  number  of 
cases  was  only  thirteen  and  the  number  of  deaths  one; 
altogether  too  small  a  group  to  give  reliable  returns. 

The  figures  for  our  series  are  again  in  close  agree- 
ment with  those  of  other  observers.  The  lethal  rate  of 
scarlet  fever  varies  considerably  with  time  and  place, 
depending  on  'the  severity  of  the  epidemic.  An  aver- 
age of  8.4  per  cent,  is  given  by  McCollom  on  the  basis 
of  over  37,810  cases  in  Bo^ston,  covering  a  period  of 


3 


twenty-eight  years.  Some  hospital  figures  show  a 
somewhat  higher  lethal  rate.  According  to  Osier,  90 
per  cent,  of  all  the  scarlet  fever  deaths  are  of  children 
under  10;  our  figure  was  92  per  cent.  As  our  cases 
were  drawn  from  all  parts  of  the  country,  no  particu- 
lar epidemic  is  unduly  represented,  and  the  findings  are 
close  to  the  best  previously  reported  averages  for  large 
series  of  cases  covering  many  years. 

The  90  deaths  showed  complications  in  62  cases. 
In  11  of  these  there  was  a  distinct  kidney  involvement. 
Heart  conditions  were  recorded  in  7  fatal  cases.  Pneu- 
monia was  present  in  13  cases.  There  were  4  cases 
of  meningitis  and  1  case  of  otitis  media.  In  9  cases 
the  scarlet  fever  was  complicated  by  the  presence  of 
other  acute  infections  like  diphtheria  or  measles.  The 
other  complications  are  few  in  number,  and  are  too 
vaguely  stated  to  justify  special  attention.  Among 
the  1,063  sur\dvors  we  find  similarly  a  record  of  31 
cases  of  nephritis,  31  cases  of  otitis  media,  22  cases  of 
adenitis,  and  11  cases  of  pneumonia.  It  is  very  prob- 
able, however,  that  in  the  nonfatal  cases  the  compli- 
cations were  not  stated  as  fully  as  could  be  wished, 
certainly  not  as  fully  as  is  usually  done  in  hospital 
practice.  Osier,  for  example,  records  the  presence  of 
nephritis  in  from  10  to  20  per  cent,  of  his  cases.  Heart 
complications  are  also  recorded  in  higher  proportions 
in  other  series.  Middle  ear  trouble  is  reported  in  20 
per  cent,  of  all  cases  by  Fisher,  and  the  same  author, 
in  a  series  of  over  6,000  cases,  records  14  per  cent,  that 
had  adenitis.  We  must  not  infer,  however,  from  the 
smaller  number  of  complications  recorded  by  us  that 
the  cases  were  less  severe  than  is  usual.  We  have 
already  shown  that  the  lethal  rate  is  very  close  to  the 
average  obtained  by  other  investigators  on  the  basis 
of  large  exposures  over  long  periods. 

We  are  now  concerned  with  the  tracing  of  the  1,063 
cases  in  which  the  patients  survived,  and  we  shall  see 
whether,  during  the  following  years,  the  complications 
or  impairments  which  they  suffered  really  affected 
their  chances  of  life  to  any  appreciable  degree.  There 
were  represented,  during  the  entire  subsequent  period, 
3,583  years  of  life.  This  means  that  the  1,063  per- 
sons were  under  observation  for  an  average  period 
of  3.4  years.  The  expected  number  of  deaths  for  this 
group  of  survivors  was  then  calculated.  The  mortality 
rate  actually  experienced  by  the  company  for  the  cor- 
responding age.  sex  and  color  during  the  years  covered 
by  the  study  was  used  as  ^  standard.     According  to 


this  measure,  we  had  a  right  to  expect  18.6  deaths. 
As  a  matter  of  fact  we  experienced  only  18  deaths. 
Far  from  showing  a  higher  mortality,  as  was  the  case  in 
the  typhoid  fever  study,  we  found  a  death  rate  ahnost 
identical  with  the  expectation  based  on  our  general 
mortahty  experience.  The  actual  mortahty  was  97 
per  cent,  of  the  expected.  We  may,  therefore,  say 
that  during  the  period  covered  by  our  observations  the 
mortality  of  the  survivors  as  a  group  shows  appar- 
ently no  increase.  Table  3  presents  a  comparison  of 
the  actual  and  expected  mortality  among  the  1,063 
survivors,  classified  by  age  period. 

The  most  favorable  condition  is  found  in  the  age 
period  2  to  5  years.  The  actual  number  of  deaths  is 
somewhat  higher  than  expected  in  the  age  period  6  to 
10  (117  per  cent.).  The  deaths  are  considerably 
higher  in  the  period  11  to  15  (244  per  cent.).  In  view 
of  the  small  number  of  persons  exposed  in  this  age 
period  the  figures  must  not  be  considered  as  entirely 
decisive,  although  they  are  suggestive. 


TABLE     8.— COMPARISON     OF     ACTUAL     AND     EXPECTED     MOR- 
TALITY    AMONG    1,063    PERSONS     IN     FIVE     YEARS    FOL- 
LOWING    RECOVERY     FROM    SCARLET    FEVER; 
CLASSIFIED    BY    AGE     PERIOD 


Number  of 

Number  of 

Number  of 

Actual 

Age  Period 

Years 

Expected 

Actual 

Deaths  per 

of  Life 

Deatlis 

Deaths 

100  Expected 

All  ages 

3,583.46 

18.61 

18 

97 

2  to   5 

908.29 

9.16 

7 

76 

6  to  10 

1,614.3.5 

6.0O 

7     . 

117 

11  to  15 

699.53 

1.64 

4 

244 

16  to  20 

194.88 

0.62 

21  to  30 

105.66 

0.67 

31  to  40 

60.75 

0.52 

It  is  of  interest  to  find  that,  of  the  eighteen  deaths 
which  occurred  in  the  four  years,  three  showed  a  rec- 
ord of  endocarditis  on  the  death  certificates;  these 
cases  may  reflect  the  impairment  resulting  from  the 
original  scarlet  fever.  There  were  five  deaths  from 
respiratory  diseases  and  four  from  tuberculosis.  The 
remainder  were  scattered  among  a  number  of  causes 
which  have  no  particular  interest  for  us.  Strangely 
enough,  there  were  no  deaths  from  kidney  diseases. 
Apparently,  among  the  survivors  of  the  primary  dis- 
ease, the  kidneys  were  not  sufficiently  impaired  to 
cause  early  death. 

We  are  concerned,  therefore,  with  explaining  the 
difiference  between  the  actual  experience  and  that 
which  was  expected  on  the  analogy  of  our  typhoid 


fever  investigation.  A  comparison  of  the  two  sets  of 
conditions  is  useful,  moreover,  because  it  helps  to  a 
clearer  insight  into  the  kind  of  impairment  which 
results  from  scarlet  fever.  In  the  typhoid  fever  cases 
there  was,  after  recovery,  a  marked  increase  in  the 
number  of  tuberculosis  deaths.  An  increase  was  also 
noled  in  the  number  of  deaths  from  organic  diseases 
of  the  heart,  but  this  was  not  so  great.  In  our  scarlet 
fever  cases,  on  the  other  hand,  there  is  no  positive 
evidence  of  an  increase  in  the  number  of  tuberculosis 
cases.  The  three  deaths  from  endocarditis  are  too  few 
to  justify  any  conclusion  as  to  serious  heart  impair- 
ment in  the  survivors.  The  interesting  fact  is  the 
absence  of  deaths  from  kidney  diseases.  It  would 
seem,  then  (and  this  is  confirmed  by  clinicians),  either 
that  impairments  of  the  kidneys,  which  are  so  common 
in  scarlet  fever,  are  severe  enough  to  cause  immediate 
death,  or  that  in  the  survivors  the  injurious  effect  is 
not  sufficiently  great  to  kill  wathin  the  next  five  years. 
Apparently,  in  the  cases  in  which  there  Avas  recovery, 
there  has  not  been  enough  destruction  of  kidney  tissue 
to  prevent  subsequent  regeneration.  It  is  quite  pos- 
sible, of  course,  that  ultimately  there  may  be  an 
increase  in  the  expected  number  of  deaths  from  kidney 
lesions,  although  such  a  consequence  may  not  mani- 
fest itself  until  ten  or  more  years  have  elapsed  after 
the  initial  incidence  of  the  scarlet  fe\er.  AVe  hope  to 
clear  up  this  possibility  in  the  future. 

DEATH  RATES  FROM  SCARLET  FEVER 

Although,  as  I  have  indicated,  the  sequelae  of  scar- 
let fever  are  apparently  not  an  appreciable  factor  in 
the  mortality  of  survivors,  it  should  not  be  overlooked 
that  the  disease  itself  still  constitutes  an  important 
factor  in  child  mortality.  The  disease  has  not  shown 
the  same  amount  of  decrease  in  frequency  during  the 
last  fifteen  years  that  has  been  observed  in  connection 
with  other  infectious  diseases.  The  death  rate  fluc- 
tuates about  the  figure  10  per  hundred  thousand.  In 
1900  the  scarlet  fever  death  rate  in  the  registration 
area  was  10.2;  in  1913  the  rate  was  8.7.  In  spite  of 
this  drop,  there  were  a  number  of  years  in  the  inter- 
vening period  when  the  rate  was  even  higher  than  the 
1900  figure.  Light  is  cast  on  the  mortality  conditions 
from  this  cause  by  the  industrial  mortality  experience 
of  the  Metropolitan  Life  Insurance  Company,  the  fig- 


Lires  for  which  are  presented  in  Table  4.  These  rates 
are  new  and  have  the  particular  advantage  of  accuracy. 
The  count  is  correct  not  only  for  the  number  of  deaths 
from  scarlet  fever,  but  also  for  the  number  of  per- 
sons living  in  the  various  classes  by  which  the  mortal- 
ity is  enumerated.  A\'e  are  able  to  present  rates  bv  age 
period,  sex  and  color. 

The  most  interesting  fact  indicated  by  this  table  is 
the  markedly  lower  mortality  of  the  colored.     Gen- 

TABLE     4.— MORTALITY     EXPERIENCE     FROM     SCARLET     EEVER, 

1911-1914,   3,778    DEATHS    CLASSIFIED   BY    COLOR,    BY    SEX   AXD 

BY      AGE      PERIOD;      DEATH     RATES     PER     HUNDRED 

THOUSAND;     METROPOLITAN     LIFE     INSURANCE 

C  OMPANY— INDUSTRIAL     DE  P  ARTME  NT 


Age 

Per- 

White 

White 

Colored 

Colored 

Period 

sons 

Males 

Females 

Males 

Females 

AU  ages 

11.1 

13.8 

11.2 

2.7 

2.2 

Under   5 

64.4 

71.1 

64.7 

17.4 

■n.9 

5  to    9 

29.5 

27.3 

31.0 

10.3 

7.3 

10  to  14 

8.0 

7.2 

9.7 

5.3 

2.4 

15  to  19 

3.5 

3.8 

3.7 

0.5 

2.2 

20  to   24 

1.8 

1.1 

2.9 

0.4 

25  to   34 

0.9 

0.7 

1.3 

0.3 

0.2 

35   to   44 

0.5 

0.6 

0.5 

0.5 

45  to   54 

0.2 

0.2 

0.1 

0.5 

55  to   64 

0.3 

0.2 

0.3 

0.7 

65   to   74 

75  and  over 

0.8 

1.4 

TABLE     5.— INCIDENCE     OF     1,1,53    SCARLET     FEVER    CASES, 
1911-1912,    BY    MONTHS 


Month  of                 j  No.  of 

Occurrence  Cases 

January 105 

February Ill 

March 133 

April 141 

May 149 

June 119 


Month  of                 I  No.  of 

Occurrence  Cases 

July 53 

August 45 

September 36 

October 71 

November ;  82 

December ,  108 


erally  speaking,  the  death  rate  for  colored  children  is 
about  one  fourth  that  of  the  whites.  This  fact  may 
serve  medical  investigators  as  a  point  of  departure  for 
a  study  of  the  etiology  of  this  still  obscure  disease. 


SEASONAL     DISTRIBUTION     OF     SCARLET     FEVER     CASES 

Our  study  has  also  made  possible  a  presentation  of 
the  seasonal  distribution  of  the  1,153  cases  of  scarlet 
fever.    This  distribution  is  shown  in  Table  5. 

From  January  the  frequency  of  the  disease  rises 
rapidly  until  May,  when  the  maximum  number  of 
cases  occurs.     Thereafter  there  is  a  rapid  drop  in  the 


number  until  September,  whicb  is  marked  by  the  mini- 
mum. For  the  remainder  of  the  year  there  is  a  rise 
in  the  curve,  which  stops  at  a  shghtly  higher  point  than 
that  experienced  in  the  previous  January. 

The  accompanying  chart  shows  the  seasonal  distri- 
bution of  these  scarlet  fever  cases  compared  with  the 
distribution  of  20,984  cases  reported  by  the  Depart- 
ment of  Health  of- New  York  City  for  the  two  years 
1914-1915.  The  cases  which  were  reported  in  each 
month,  per  thousand  occurring  in  the  entire  year,  are 
shown. 


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x. 

Seasonal    distribution    of    scarlet    fever    cases. 

The  two  series  are  clearly  similar  in  their  distribu- 
tion. The  largest  number  of  deaths  occurs,  in  both, 
during  the  months  of  April  and  May,  and  the  fewest 
number  in  September.  It  is  during  the  summer 
months  that  the  cases  are  rarest  in  their  occurrence, 
and  it  is  quite  possible  that  this  condition  is  corre- 
lated with  the  absence  of  children  from  school  during 
the  vacation  period.  With  the  opening  of  school  in 
September  the  number  of  cases  begins  to  increase 
rapidly,  reaching  the  maximum  in  the  spring.  Of 
course,  attendance  at  school  is  not  the  only  factor, 
since  certain  respirator}^  diseases  show  a  similar  sea- 
sonal distribution,  and  are  clearly  subject  to  the 
v/eather  c®nditions. 


8 


DATE  DUE 


COLUMBIA  UNIVERSITY  LIBRARIES 


A  Study  Of  225-? 

fever  ^^  °^ses  of  o^«  , 


